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This invention pertains to control circuits for radios and, more particularly, to a control circuit that includes switches with reversible functions and a display for displaying information in inverted and non-inverted orientations.
The recent trend in the design of portable radios, such as hand-held transceivers and selective call paging receivers, has been to reduce the overall size of the radio and to add more functions and options. When more functions are added, however, additional controls must be provided to permit the user to select a particular operating parameter. But, adding controls conflicts with the trend towards smaller radios since there is less space available to add additional switches and other control devices.
To increase the number of selectable functions while reducing the number of switches, a radio controller could be designed to include a "menu" of possible function parameters that could be sequentially selected by "scrolling" through the menu by the selective activation of one of two switches. One switch would scroll "up", i.e., from the last entry in the menu towards the first, while the other switch would scroll "down", i.e., from the first entry towards the last. A display could be positioned on the top of the radio to indicate the particular parameter selected. Arrows, one facing up and one facing down, could be placed adjacent the appropriate up/down switch as indicia of scrolling direction.
Such a system would work well, provided the radio is always positioned in the same orientation during use. Such is not the case, however, with portable radios. Generally speaking, there are two preferred orientations for portable radio operation. In the first orientation, the radio is held at an angle such that the front face and the top (which includes the display) are oriented towards the user. The second preferred orientation usually results when the user attaches the radio to an article of clothing such as a belt. In the second orientation, however, the user not only views the display upside down, but the up/down indicia adjacent the switches now face in the opposite direction and the function of the switches is reversed (that is, if the up and down switches were positioned on opposite ends of the display, the switch to the right of the display may have been the up switch in the first orientation, but the switch on the right of the display in the second orientation would then be the down switch).